Heat sealed bag



Jan. 10, 1956 w. H. BoKl-:NKRQGER 2,730,295

HEAT SEALED BAG Filed Oct. 2, 1952 2 Sheets-Sheet l uma. .uuumm' Jan. I0, 1956 w. H. BOKENKROGER HEM SEALED BAG 2 Sheets-Sheet 2 Filed Oct. 2

, ATTORNEY United States Patent() HEAT SEALED BAG William H. Bokenkroger, Hudson Falls, N. Y., assignor to Union Bag & Paper Corporation, New York, N. Y., a corporation of New Jersey Application Gctober 2, 1952, Serial No. 312,769 4 Claims. (Cl. 229-57) The present invention relates to improvements in heat sealed bags. More particularly it pertains to a square bag having cut-outs which facilitate securing of the bottom flap and improve the bottom or end closure.

In manufacturing paper bags of the square type each bag tube is cut successively from a continuous gusseted flat tube so that the top cut-olf of one becomes the bottom cut-oli:` of the next. This cut-off is made to provide an extension or lip on one side at the top of the bag tube which results in a corresponding cut-back or reverse cut on the sarne side at the bottom of the bag tube. Paste is applied to the cut-back portion and the longer side or Hap of the tube is folded over the cut-back to form the bottom. It is evident that this type of cut-off is made primarily to provide a pasting surface to complete the bottom. However where a bag tube has an inner layer or coating of a heat sealable material, such as, for example, polyethylene, plasticized polyvinyl chloride, e. g. KoroseaL halogenated rubber sheeting, e. g. Pliofilm, and films formed of thermoplastic synthetic resins, such as a copolymer of vinyl chloride and vinyl acetate, e. g. Vinylite sheeting, and the like, it will be seen that the usual cut-off exposes such heat sealable material at the cut-back portion of the bottom. This immediately creates a problem since special adhesives are required to paste this heat sealable surface to the side of the bag to form the bottom. For instance, in the case of' polyethylene it is necessary to employ a rubber base adhesive, which is expensive and very dicult to handle. Because of its extreme tackiness it is a nuisance in the paste dishes and on the other portions of the equipment with which it comes in contact. Since the advent of new heat sealable materials, it has been felt that it would be a distinct advantage to overcome this diliculty and it is accomplished by means of the present invention.

Cther objects and advantages of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises an article of manufacture possessing the features, properties and the relation of elements which will be exemplified in the article hereinafter described and the scope of the application of which will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawing, in which:

Figure 1 is a plan view of a broken away and prior to turning form a bag embodying the Figure 2 is a sectional view on a somewhat enlarged scale taken along the line 2-2 of Figure 1;

Figure 3 is a plan view of the bottom end of the tube of Figure l with the end portion folded and pasted;

Figure 4 is a perspective view of a corner of the bottom end of the tube of Figure 1;

Figure 5 is a plan view of a bag tube illustrating a conventional cut-eti, prior to turning up the bottom;

Figure 6 is a plan view of a tube with a modified form gusseted tube, partly up the end portion to present invention;

of cut-out, prior to turning up the end portion to form a bag embodying the present invention;

Figure 7 is a plan view of the bottom end of the tube of Figure 6 with the end portion folded and pasted;

Figure 8 is a plan view of a tube with a further modied form of cut-out, prior to turning up the end portion to form a bag embodying the present invention; and

Figure 9 is a plan view of the bottom end of the tube of Figure 8 with the end portion folded and pasted.

Referring more particularly to the drawings there is shown in Figures l and 2 a duplex bag tube 10 having plies 11 and 12, with appropriate side folds and gussets.

The inner ply 11 is coated on the inside surface with a heat sealable material and has its overlapping marginal edges 11a and 11b secured together with adhesive 11e to form a longitudinal seam. Similarly the outer ply 12, which is uncoated, has its overlapping marginal edges 12a and 12b secured together with adhesive 12e to form a longitudinal seam. Such plies are usually held in their relative positions by spot pasting. The tube is provided with a fold or crease line 13 along which the end portion of the tube may be folded to form the bottom. The tube is closed at the end by a band of heat sealing 14.

As shown in Figures l and 4, the bottom cut-off of the tube runs straight across except for a cut-out 15 on each side of the end portion through the upper wall of the tube and the upper portions of the gusset. Such cut-out is confined to the gusset area, that is between the outer edge of the tube and the depth of the gusset indicated by the fold line 16, and cannot extend above the top edge of the heat seal band 14, although it can run into it. If the cutout runs beyond such boundaries, it will either expose the heat sealable surface, thereby creating the pasting difliculties mentioned above, or cause leakage above the heat seal band. By employing the method described above of cutting the bags successively from a continuous gusseted tube, it will be seen that such cut-outs result in extensions 17 in the upper portions of the gussets at the top end of the tube. In lother words the cut-outs at the bottom form corresponding extensions on the same side of the tube at the top. If the extensionsat the top of the bag are objectionable for any reason, they may be cut olf to provide a flush-cut top.

To complete the bag bottom, adhesive is applied, as shown at 18, and the end portion of the tube is folded upwardly along the fold or crease line 13. This results in the folded and pasted bottom illustrated in Figure 3, In some cases it has been found advantageous in spot pasting the plies to each other to place some adhesive in the area between the cut-outs 15 near the bottom end of the tube. This causes the outer ply to lie flush against the bag face in the finished bag. Of course Where the heat sealing band extends to the bottom end of the tube extra adhesive in such area is unnecessary.

lt will be seen in Figure 5 that a similar bag tube with a conventional cut-off has the heat sealable surface entirely exposed in the cut-back area 19 at the bottom of the tube. This consequently requires that the adhesive shown by the band 20 must be a special type to secure the heat sealable material to the side of the bag when the bottom is formed. This disadvantage is effectively over come by the present invention.

Figures 6 and 8 each show a modified form of cut-out 15 which can be provided on each side of the end portion through the upper wall of the tube and the upper portions of the gussets, such cut-outs being circular in the tube of Figure 6 and semi-circular in the tube of Figure 8. It will be understood that these cut-outs may assume any configuration, the primary purpose being to expose the portion is folded over the cut-outs and secured to form 3.'. the bottom or endV closure. Figures 7 and 9 show the bottom end's ofthe' tubes ofFigures 6"'a'nd'8w`itl tle end" portions folded and pasted.

In the illustrated embodimentsof-the .invention, a.du= plex bag is shown withtheinner surfacefof'thetinner. ply coated .withlieat scalable material. It will b'eunder'stood that the ypresent invention i'sequally applicable. toa single ply baghaving it'sinsid'e surfaccior. a portion.-.thereo.so coated; totlaminated ing difficulties mentionedabove.

From the foregoing. description. and.. accompanying drawings it will bev apparentthat. thek cut-outs. ofthe .p'rese ent invention are a distinct improvementover thatshbwn in the conventional squarebag.of.Figure..5.particularly where heat .sealing is. to hev employed. Since. certain changesmay be madezinthe aboveproduct anddifferentembodiments of the inventiomcoul'd be made without def parting-from. the scope thereof, it, is. intended that. all matter.v contained in theabove descriptionv or shown in the accompanying drawings shallbe interpreted asillustrative and not in .a limiting sense@V v It is also tobe understoodthat the following .claimsare intended to rcover all the generic and speci'efeaturesof bags .or any bags involving the past-f the invention herein described,-v andall' statements'of'the scope of the inventionwhich, as v.at-matter of language, might be said to fall therebetween.

Having described my invention, what I claim as new and'desire to secure by Letters Patent is:

l. A bag formed from a gusseted'tubewith. a heat scalable inner surface and. comprisingrupper andfilrower walls, an endportion, aitransverseheat.seal-intheend. portion. closing thetube, and eut-outs in one .wallon each side of the end portionthrough the .said wall andthe` halves of the gussetsadjacent andconnected tofthe saidy wall, said cut-outs being locatedl in the..gusset.area and extending from the bottom edgeof.. the tube to .below the.. top edgeof the heat seal with all wallsalong thebottom. edge flush cut except at such cutouts,.the endfportion being folded over the cut-outs and .adhesivelyr secured to the wall to form an end closure.

2. A bag formed from ay gussetedtube with, al heat sealable inner surface at least adjacent theendof the tube to be closed and comprising upper. andlowerwalls, an end portion, a transverse heatseal. inthe 4end portion'.l closing the tube, and cut-outsin onewall on.each.side of the endlportion through said'wall and the halvesof .the

gussets adjacent and connected to the said wall, said cutout's'leing' located inthe gusset area and extending'from the bottom edge of the tube to below the top edge of the heat seal with all walls along the bottom edge tiush cut except at such cut-outs, the end portion being folded over the cut-outs and adhesively secured to the wall to form an end closure.

3. A bag formed-froma-.gusseted tube with a heat sealable inner surface and`compri`sing upper and lower walls,

0 a=transverse fold lineld'eningfanend portion of the. tube,

a transverseheatse'al inltheendportion closing the'tube, and cut-outs in one Wall on each side'of the'end portion throughfsaidawall: and.. the: halves of the gussets adjacent and connected to the said wall, said cut-outs being located in the gusset area andextending from the bottom edge of the tube to below the top edge of the heat seal with all walls along the bottom edge ush cut except at such cutoutsthe end portion l.being folded alongl the fold line over tlie'cutfouts and adhesively secured to the wall to form an end'closure.

4. A bag formed v.from a gusseted tube with a heat sealableinner surface at least adjacent the end. of the tub'etobecl'osed andcomprisingupper and lower walls, a transversefold'line defining an end portion of the tube, a transverse heat seal between .thefold line and the end of thettube closing, the tube, cut-outs in the upper wallv on each side oftheend portion through the said wall and the upper halves of .the gussets adjacent and connected to the said.wall,.siaidlcutouts being located in the gusset area andextending from the bottom edge of the tube to below the top edge offthe Heat sealwith all walls along the bottom edge flushcut except atsuch cut-outs,A and a transverse lineof'adhesive ontheupper wall adjacent the lower end`ofthetube, the endportion being folded over along the fold lineand secured to the upper wall to complete the end closure.

References Citedtin thetile of this patent UNITED STATES PATENTSr 392364` McCulla Nov. 13, 1888 1,988462'l i Royalr Ian. 22, 1935 0623318`A Sterling- Dec. 1, 1936 2g078-,467-v Sterling Apr. 27; 1937 2;3.12,280 AveryA Feb; 23, 1943` 22,333,440' Potdeviny Nov; 2, 1943 

